Bi_4Ti_3O_(12)纳米片的低温合成与光致发光特性研究

Study on the fabrication and photoluminescence of Bi_4Ti_3O_(12) nanoplates via hydrothermal method

以Bi(NO3)3.5H2O和Ti(OC4H9)4为原料,NaOH为矿化剂,聚乙二醇(PEG)为添加剂,采用水热法制备形貌规则的Bi4Ti3O12纳米片.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线荧光光谱(XRF)研究产物的物相、显微结构和组成,利用分子荧光光谱仪(PL)研究产物的光致发光特性.结果表明水热合成的Bi4Ti3O12纳米片为正交相层状钙钛矿结构,平均边缘尺寸大约200 nm,厚度10～20 nm,主要沿着平行于(111)面和垂直于(111)面的二维方向生长.室温下Bi4Ti3O12纳米片在470.4nm处具有蓝—绿发光,在399.3 nm和417.6 nm处具有紫光发射特性,初步认为是纳米片表面的氧空位和铋空位所引起的,同时在380 nm和516 nm处存在高能带边和低能带尾.

Bismuth titanate （Bi4Ti3O12） nanoplates have been synthesized by hydrothermal method, using bismuth nitrate and titanium butoxide as the starting materials, sodium hydroxide as the mineralization and polyethylene glycol （PEG） as the additive. The phase and microstructures were characterized by X-ray diffraction （XRD）, and scanning electron microscopy （SEM）, transmission electron microscopy. The photoluminescence （PL） was performed at room temperature by a RF-540 fluorescence spectrometer. The results showed that the Bi4Ti3O12 nanoplates were orthorhombic structure with the average sizes of about 200nm and thickness of 10-20 nm, and with two growth directions being nearly both perpendicular to the （111） planes and parallels to the （111） plane. A blue-green emission band peaking at 470. 4 nm and an violet emission band centered at 399. 3 nm and centered at 417. 6 nm, as well as two weak emission bands centered at 380 nm and 516 nm were observed at room temperature. The oxygen vacancies and the bismuth vacancies in the nanoplates should be responsible for the blue-green emission. The violet emission can be attributed to the radiation combination of the electron on the broad donor energy resulting from the oxygen vacancies with the hole on the valence.band. The bands at 383 nm and 516 nm may be derived from the near band-edge emission and the deep-level emission.